The Department of Justice gave its approval to both companies to move forward with the purchase, after several months of investigation into whether the deal could damage competition.

Clearance had hit hiccups about the licensing of Java, the programming language owned by Sun that runs on more than 7 billion electronic devices around the world including mobile phones and PCs.

Despite Sun's struggles in recent years, the deal came as a surprise when it was announced in April – largely because Sun had been locked in mercurial talks with another rival, IBM. Although the legendary computer company had made a higher initial bid, discussions broke down after IBM reduced its valuation over competitive concerns.

The Oracle deal still has to get the approval of the European Commission, which has traditionally taken a more robust hand to regulating technology companies. Potential antitrust questions surrounding the deal include the future of Sun's MySQL database – an open-source product that it bought in 2008 for $1bn.

There had been concerns that bringing that together with Oracle's own database products would create a possible anti-competitive situation - fears that MySQL founder Martin Mickos, among others, attempted to quell.

European regulators have said they will make a decision by September 3.